1. Field
The present disclosure relates to a vehicle and an electric motor control method for a vehicle.
2. Description of the Related Art
A hybrid vehicle described in Japanese Unexamined Patent Application Publication No. 2003-134602 includes an engine, a generation electric motor driven by the engine, a drive electric motor, and a battery acting as an energy store for electric energy (see FIG. 1 of Japanese Unexamined Patent Application Publication No. 2003-134602).
In the hybrid vehicle described in Japanese Unexamined Patent Application Publication No. 2003-134602, in addition to braking control to reduce the speed of a vehicle by controlling a braking device based on the operation amount of a brake pedal and a deceleration request command from a vehicle speed control unit, regenerative cooperative braking is also performed to add, as braking force, regenerative torque from the drive electric motor.
In the hybrid vehicle described in Japanese Unexamined Patent Application Publication No. 2003-134602, in a regeneration mode of the drive electric motor, regenerative energy generated by the drive electric motor in the regeneration mode is stored as electric energy in the battery. Control is described therein for cases in which the desired deceleration is not obtainable because the battery is unable to absorb the regenerative energy of the drive electric motor due to the state of charge of the battery. In such cases, the generation electric motor is controlled so that the q-axis current is 0, the d-axis current<0, and regenerative energy from the drive electric motor unable to be absorbed by the battery is lost as heat in the generation electric motor, the desired deceleration is obtained by absorbing the excess electric energy (see Japanese Unexamined Patent Application Publication No. 2003-134602 paragraph [0019], FIG. 3A, and FIG. 3B).